Re: Driver problem
It is also possible that the virus was resident in your Restore Point file, once you have scanned with an AV and are certain your pc is clean you might like to run sfc /scannow which is the XP system file checker, this will repair any corrupt Windows system files without having to run a repair install. My guess would be that this shared .dll is from one of the deleted pop up spyware/malware that you have already partially removed. I would also run Adaware SE and Spybot Search and Destroy (or your preferred anti spyware programme) You do not specify what your AV is, so if it has allowed you to become infected once I would seriously look at it's capabilities, there are many good online scans, my preferred at the moment is BitDefender but there are lots of others, Trend Micro Housecall and Panda Activescan to name a couple.
Once that is complete you need to open Device Manager (Right click My Computer > Properties > Hardware tab > Device Manager and look to see if any of your devices have a yellow ! mark next to them, if there are some present you will probably need to reinstall their drivers.
To run sfc /scannow:
1/. Insert your XP cd , cancel auto run
2/. Start > run
3/. Type in sfc /scannow (note the space between sfc and the /, failure to type this correctly will result in no scan)