Assuming you're running WinXP/Vista: So long as Windows is up-to-date with it's windows updates (very important to keep on top of that), and you have had antivirus software installed as your next priority *and* have kept that up-to-date too (also very important ..people forget that one), your PC should be okay with respect to viruses. So it should be safe to plug in the drive with your other documents and your antivirus software will pick-up on anything present on the bootblock or in the files on this drive.

For paranoia, once you've plugged-in the drive with your old files, do a full scan of that drive. You can be pretty confident of things then. ..For extra safety, anti-spyware tools like Spybot Search and Destroy could be worth a look too.

The key with antivirus is to have your antivirus software installed and up-to-date before you encounter something bad. Antivirus software is meant to stop you from getting the virus in the first place. Once a PC *has* a virus, well you might be able to remove it, but if it has a root-kit component it can hide itself from the OS, so how would you know? Better to reformat and reinstall Windows from a known clean source if an infection has taken.

You could just proceed with a clean XP install and then install a reliable virus scanner (ESET NOD32 is a good one, it detects a large percentage of known viruses), and also install Malwarebytes or SpyBot or a similar tool to periodically scan your system in addition to doing regular virus scans. Hopefully a virus such as that will alert the antivirus software if and when it activates.

I agree with the other listings that you should do a full install of windows with all updates first. Next load your anti-virus and update, then run a full scan. However, if your anti-virus doesn't run a boot scan (a scan before windows boots up) you might want to consider installing one that will first. Such as Avast! antivirus home version (free and highly rated). Once installed you can schedule a boot scan to run prior to windows loading. This is your best chance to catch those pesky viruses trying to hide out. The one other thing to remember is to turn off windows restore in Control Panel during this process as it can actually reinstall the virus after it's been deleated or quaranteed. Once you get a clean scan you can then remove Avast! and install your own anti-virus or you can keep Avast! as it does a great job. I would double check with an anti-malware/spyware program like AdAware, A-Squared, or Spybot-Search&Destroy. If you run your antivirus in memory and keep things up to date you should be OK.

If you have done all your Windows updates and have installed the latest version of a anti-virus program, then you should be ok. When doing Windows updates, be sure to go back to the update window over and over until it shows, no critical updates available. Some people make the mistake of doing one update, not realizing that some updates have to be installed before the update process will detect the need for additional updates. Also, don't use an old anti-virus program (like 2006) and think that you can simply update the list of viruses from the internet. Buy a new anti-virus CD every year. And don't download the program when the company offers to sell you the next years update over the internet. Go to Walmart or Costco or somewhere else and buy the CD. Once you have installed and updated Windows and your anti-virus program, you should be ok to plug in the external HD. (I am assuming that your Docs are on an external CD). Then scan the external HD and you should be set to go. If my Docs were in Word, I would scan the external HD before I installed Office on my computer.