Download and run these programs to start with:
Reg Cleaner is a good utility that I have had no problems with:
http://www.worldstart.com/weekly-dow...cleaner4.3.htm
On Reg Cleaner, go to Tools, Registry Clean Up, Do Then All. When it has finished running, choose Select, All then click Remove, click Done, then Exit. Do not be surprised if you find 100 or more items on the first pass!
AdAware SE is also a good program:
http://www.lavasoftusa.com/support/download/#free
Download and install this. Check for updates. Run this program an select all items if finds and delete them all, both Critical and Negligible objects.
I will have to look into what Firefox needs to Trend, or someone else may get back with you.
Are you running out of memory by any chance?
JamesO