Parallels 3.0 just quit on me!!

I use parallels 3.0 for spacial mapping programs (AutoCAD, arcview, Mapinfo) on windows XP software and have found the program to be generally very reliable.
I have been encountering sluggish response time, and therefore I decided I needed to allocate more RAM to the VM. I clicked on the slider bar, and selected from 512 to 2000, as I have 4gb of available ram.
Once I did this and attempted to boot up, Parallels sent me an error message:
"Error occured while trying to interact with Parallels driver! Parallels Desktop is either not installed or/and configures or has integrity problems, which prevent it from operating properly. Please reinstall the Parallels Desktop"

Now I have ordered the upgrade version, as I am currently in the field, but based on negative reviews, I do not feel I need to upgrade from 3.0 to 4.0. I have had a generally positive experience with 3.0 and would like to continue to use this until I require an upgrade.
I do not have a copy of the parallels disc with me (I am in the field) and I need to use these mapping programs. How do I go about re-installing 3.0 without losing my windows and all the licensed programs I have on there?
As I mentioned, I have many programs that are licensed to me as the primary user, and none of the backup software with me.

 

You can follow http://kb.parallels.com/en/4790,
Download can be performed from http://download.parallels.com/v3/en/GA/Parallels-Desktop-5626-Mac-en.dmg
Your Virtual Machines will be untouched

 

So I managed to get parallels back running,
and now Windows has deleted all the files I installed. Basically I have gotten a "Fresh" windows XP. My MacOS recogizes that all the files are still stored within parallels somewhere. Where would they be kept?

 

By default Parallels Desktop 3 Virtual Machine folders are kept in /Users/<your_username>/Documents/Parallels. In case you are unable to locate this folder please try looking for the VM files manually (via search or spotlight). You are looking for .pvs and .hdd files.