что будете делать если винда слетит и вся инфа сотрётся?

Отформатированием диска. При этом удаляется все информация с компьютера. Это может сделать вирус, или человек.

Не верь таким, кто гонит на "семерку". Я юзаю с самого начала "семерку" - никаких нареканий. А тот, кто разочаровался, наверняка паленую поставил, или криво установил/настроил. Вот и лезут косяки. Как обычно, виновата "прокладка", между стулом и монитором.
По вопросу - на диске Д не сотрется, при условии, что ставишь на диск С. А даже если и на Д поставишь, то твои файлы останутся целыми, при условии, что при установке винды не будешь форматировать раздел.

При установке он запрашивает удалить всё или устанавливать поверх

для этого и делят диски  , на одном система  , на другом файлы

Активация слетела. Либо качай активатор.
Либо переустанавливай ОС.

Под винду желательно всегда удалять раздел и создавать заново, что бы не мучаться с "прошлыми жизнями".

Держи http://www.smsinfo.in.ua/soft/4085-gismeteo-trejj-prognoz-pogody..html

http://www.sevenforums.com/tutorials/5966-run-commands-windows-7-a.html
Administrative Tools

Administrative Tools = control admintools
Authorization Manager = azman.msc
Component Services = dcomcnfg
Certificate Manager = certmgr.msc
Direct X Troubleshooter = dxdiag
Display Languages = lpksetup
ODBC Data Source Administrator = odbcad32
File Signature Verification Tool = sigverif
Group Policy Editor = gpedit.msc
Add Hardware Wizard = hdwwiz.cpl
iSCSI Initiator = iscsicpl
Iexpress Wizard = iexpress
Local Security Settings = secpol.msc
Microsoft Support Diagnostic Tool = msdt
Microsoft Management Console = mmc
Print management = printmanagement.msc
Printer User Interface = printui
Problems Steps Recorder = psr
People Near Me = p2phost
Registry Editor = regedit or regedt32
Resoure Monitor = resmon
System Configuration Utility = msconfig
Resultant Set of Policy = rsop.msc
SQL Server Client Configuration = cliconfg
Task Manager = taskmgr
Trusted Platform Module = tpm.msc
TPM Security Hardware = TpmInit
Windows Remote Assistance = msra
Windows Share Folder Creation Wizard = shrpubw
Windows Standalong Update Manager = wusa
Windows System Security Tool = syskey
Windows Script Host Settings = wscript
Windows Version = winver
Windows Firewall with Advanced Security = wf.msc
Windows Memory Diagnostic = MdSched
Windows Malicious Removal Tool = mrt

Computer Management

Computer Management = compmgmt.msc or CompMgmtLauncher
Task Scheduler = control schedtasks
Event Viewer = eventvwr.msc
Shared Folders/MMC = fsmgmt.msc
Local Users and Groups = lusrmgr.msc
Performance Monitor = perfmon.msc
Device Manager = devmgmt.msc
Disk Management = diskmgmt.msc
Services = services.msc
Windows Management Infrastructure = wmimgmt.msc

Conrtol Panel

Control Panel = control
Action Center= wscui.cpl
Autoplay = control.exe /name Microsoft.autoplay
Backup and Restore = sdclt
Create a System Repair disc = recdisc
BDE Administrator = bdeadmin.cpl
Color Management = colorcpl
Credential Manager = control.exe /name Microsoft.CredentialManager
Credential Manager Stored User Names and Passwords = credwiz
Date and Time Properties = timedate.cpl
Default Programs = control.exe /name Microsoft.DefaultPrograms
Set Program Access and Computer Defaults = control appwiz.cpl,,3 or ComputerDefaults
Devices and Printers = control printers
Devices and Printers Add a Device = DevicePairingWizard
Display = dpiscaling
Screen Resolution = desk.cpl
Display Color Calibration = dccw
Cleartype Text Tuner = cttune
Folders Options = control folders
Fonts = control fonts
Getting Started = GettingStarted
HomeGroup = control.exe /name Microsoft.HomeGroup
Indexing Options = control.exe /name Microsoft.IndexingOptions
Internet Properties = inetcpl.cpl
Keyboard = control keyboard
Location and Other Sensors = control.exe /name Microsoft.LocationandOtherSensors
Location Notifications = LocationNotifications
Mouse = control mouse or main.cpl
Network and Sharing Center = control.exe /name Microsoft.NetworkandSharingCenter
Network Connections = control netconnections or ncpa.cpl
Notification Area Icons = control.exe /name Microsoft.NotificationAreaIcons
Parental Controls = control.exe /name Microsoft.ParentalControls
Performance Information = control.exe /name Microsoft.PerformanceInformationandTools
Personalization = control desktop
Windows Color and Appearance = control color
Phone and Modem Options = telephon.cpl
Power Configuration = powercfg.cpl
Programs and Features = appwiz.cpl or control appwiz.cpl
Optional Features Manager = optionalfeatures or control appwiz.cpl,,2
Recovery = control.exe /name Microsoft.Recovery
Regional and Language = intl.cpl
RemoteApp = control.exe /name Microsoft.RemoteAppandDesktopConnections
Sound = mmsys.cpl
Volume Mixer = sndvol
System Properties = sysdm.cpl or Windows logo key + Pause/Break
SP ComputerName Tab = SystemPropertiesComputerName
SP Hardware Tab = SystemPropertiesHardware
SP Advanced Tab = SystemPropertiesAdvanced
SP Performance = SystemPropertiesPerformance
SP Data Execution Prevention = SystemPropertiesDataExecutionPrevention
SP Protection Tab = SystemPropertiesProtection
SP Remote Tab = SystemPropertiesRemote
Windows Activation = slui
Windows Activation Phone Numbers = slui 4
Taskbar and Start Menu = control.exe /name Microsoft.TaskbarandStartMenu
Troubleshooting = control.exe /name Microsoft.Troubleshooting
User Accounts = control.exe /name Microsoft.UserAccounts
User Account Control Settings = UserAccountControlSettings
User Accounts Windows 2000/domain version = netplwiz or control userpasswords2
Encryption File System = rekeywiz
Windows Anytime Upgrade = WindowsAnytimeUpgradeui
Windows Anytime Upgrade Results = WindowsAnytimeUpgradeResults
Windows CardSpace = control.exe /name Microsoft.cardspace
Windows Firewall = firewall.cpl
WindowsSideshow = control.exe /name Microsoft.WindowsSideshow
Windows Update App Manager = wuapp

Accessories

Calculator = calc
Command Prompt = cmd
Connect to a Network Projector = NetProj
Presentation Settings = PresentationSettings
Connect to a Projector = displayswitch or Windows logo key + P
Notepad = notepad
Microsoft Paint = mspaint.exe
Remote Desktop Connection = mstsc
Run = Windows logo key + R
Snipping Tool = snippingtool
Sound Recorder = soundrecorder
Sticky Note = StikyNot
Sync Center = mobsync
Windows Mobility Center (Only on Laptops) = mblctr or Windows logo key + X
Windows Explorer = explorer or Windows logo key + E
Wordpad = write
Ease of Access Center = utilman or Windows logo key + U
Magnifier = magnify
Narrator = Narrator
On Screen Keyboard = osk
Private Character Editor = eudcedit
Character Map = charmap
Ditilizer Calibration Tool = tabcal
Disk Cleanup Utility = cleanmgr
Defragment User Interface = dfrgui
Internet Explorer = iexplore
Rating System = ticrf
Internet Explorer (No Add-ons) = iexplore -extoff
Internet Explorer (No Home) = iexplore about:blank
Phone Dialer = dialer
Printer Migration = PrintBrmUi
System Information = msinfo32
System Restore = rstrui
Windows Easy Transfer = migwiz
Windows Media Player = wmplayer
Windows Media Player DVD Player = dvdplay
Windows Fax and Scan Cover Page Editor = fxscover
Windows Fax and Scan = wfs
Windows Image Acquisition = wiaacmgr
Windows PowerShell ISE = powershell_ise
Windows PowerShell = powershell
XPS Viewer = xpsrchvw

Open Documents folder = documents
Open Pictures folder = pictures
Open Music folder = music
Open Videos folder = videos
Open Downloads folder = downloads
Open Favorites folder = favorites
Open Recent folder = recent
Logs out of Windows = logoff
Locks User Account = Windows logo Key + L

Driver Genius.
а для надежности устанавливать дрова с диска нужно если не сам комп собирал и не знаешь своих комплектующих.