Windows 7: Windows & hanging after login

hi, My window 7 Ultimate OS is hanging after logining into to. After desktop and Task Bar appears nothing more works. Even Ctrl+alt+del also not appears. After a long break it says "Failure to Display security and shutdown options". i have gone through all the options from F8 repair options since 3 days. Opened in safemode and checked the event viewer. i found many errors in it but don't know which is causing this problem. after checking all i found this may be responsible and searched it on google and taken what ever measures they said and got an advance from login screen to desktop and taskbar appearance and hanging there (present situation).
Error: Session "ReadyBoot" stopped due to the following error: 0xC0000188, event ID:3, Source: Kernel-Event Tracing.
Plz help me. if any info more needed i'll post. i was able to get into safemode.
Note: I have a backup at the time of installation after which i have so many updates and softwares installed. If backup is restores 10s of software installation i loose. and esp. i want restore IE, Chrome and Firefox pages to restore. I have done restore point use (only 1 i have)

i have tried all the options (other than repairing with DVD sp1) like cleanboot also. With the clean boot procedure few non microsoft services (not newly installed) and many microsoft services too causing the system hang. may be this because those files myb be corrupted. if few i may reinstall them but microsoft services i don't know how to restore. so i am going for the last option to download the DVD as said in this forum and i'll use it to repair. i started Downloading it and is taking more than 15 hours (still left with 5 hours)
Now i have few doubts, plz clarify them.
1) I don't know whether my windows 7 has sp1 or not (windows 7 ultimate build 7100). after installing i installed several updates to it.
now does this "dvd from digital river" works for me?
2) plz once again clarify me about my history of IE, firefox and chrome. this repair install will not delete my history? i compulsarily need my pages to be restored.

You should be able to run sfc /scannow from a command prompt while you're booted into Safe Mode. See if this works - you might have to do it 3 times in a row with a reboot between each time.

Also, you should really make regular backups and not just have one old backup lying around that's already out of date. Backups are fairly useless if not done on a regular schedule.

Regarding your browser history: do you mean bookmarks?

Not bookmarks. pages in tabs of browsers. i have done sfc/scannow but not 3 times. i'll do it.

Ah, you mean the session history (that's what saves your open tabs when you close down the browser). No, a repair install won't delete these or any of your other applications, settings or personal data.

oh thanks. i'll start repairing it.
one more doubt is there a way to backup those tabs before repair (i have access to the Windows 7 drive (c:/) from windows XP (f:/) on another drive) and if i backup can i open them in windows XP?

tried sfc /scannow but windows says "windows resource protection does not allow to start a repair service". how to go now?