No valid system partition found

After a virus/malware attack, I tried to do a restore. There were no restore points so I forced one using ERD WIN Commander--bad idea. It turns out that all of the restore folders were empty. When I rebooted computer it would not boot because c:\windows\system32\config\system was missing. I had to do a reinstall of windows (I managed to save my documents, files, etc.) After 2 days reinstalling software and generally cleaning things up, I find a new problem. Still no restore points and I can't create one. I tried to use a defrag program and it wouldn't work. I tried to use Partition Magic and got the message "failed to find drive in internal table." I tried to defrag from within Windows but get message "No valid system partitions found." Strangely, though, the computer is running OK in spite of the fact that there seem to be no valid partitions. I have a main partition C:\ that is 76 GB, a D:\ that is 93GB, and an E:\ that is 129GB. I tried to do a reinstall from within windows but get the message "No valid system partitions were found. "
Is there some way to fix this? Or will I have to do another reinstall from the install disk? (But that's what I just did.) Or will I have to reformat the drive and reset partitions? Can I copy everything on my hard drive and copy it back after reformatting? I'm sorry about the long statement of the problem but I would truly appreciate any help you can give. Thanks.

 

Try running Disk Management and see what it says about your system drive. Right-click on the system drive while in DM and see if it offers to "Mark Drive as Active." If so, do so.

What SP level is your new install at now?

 

Thanks for responding. I had gone to Disk Management before and did so again. The box is empty--no drive(s) show up here. What do you mean by "SP level? "

 

SP = Service Pack.

That may be relevant since SP2 is required for recognition of larger partitions. Just a stab in the dark since your problem is strange to say the least.

 

Thanks again. I have an up-to-date SP2. I think it's a strange problem also. I talked to my very adept guru and it floored him too. I believe I'll have to copy everything to another disk, reformat, and copy it all back. Thanks for responding--it's much appreciated. (But, I think I'll wait a couple of days and not rush into it.)