No regedit.exe / secpol.msc after virus attack

Hi everyone,
I had a virus attack (Win32/Packed.Autoit.Gen) and after cleaning the mess (NOD32), I found out that a lot of things are missing in my computer (no admin rights, no gpedit.msc, no msconfig.exe, no regedit.exe, no taskmgr.exe, secpol.msc,....and so) and it seems that the files are either deleted or corrupted because i can"t find them (execute) and when I try to launch them via control panel it says " windows can't find...". Unfortunately i have no restore point or save and windows 7 does not have another system repair option . I used fixwin v1.2 but nothin changed .
Please help me because i don't want to rely on the install/format solutions and thank you very much :)

If you don't have an image or restore points, do you have a Windows 7 dvd to reinstall with? If so, I would wipe the drive and repartition/reformat during the install. Also, are you updating your virus protecyopn on a regular basis?

Thanks Jonathan and the others for your replies, it was the malware and I have recovered all the missing system files but I have just one problem left now, the task manager window does not open and the system says "windows can't find ...system32\taskmgr.exe", any clue ?

Hi guys again,
I tried everything that was mentioned but nothin changed and when I tried to replace "taskmgr.exe" with the file from a friend, TrustedInstaller didn't allow me to do it.
What should I do now :s ? thank you