avg7 uninstall

1st time post.
I've changed my anti virus to avast and when I tried to uninstall avg7.5 it didn't work. I've tried going to grisoft's website to reinstall and then redo the uninstall but since they no longer support 7.5 i've hit a roadblock. avg8 won't install either due to my antiquated OS (win98se). I've gone thru my computer and deleted anything to do with avg/grisoft. now everytime I start my computer a dos type screen pops up...
"cannot find device file that may be needed to run windows or a window application. the windows registry or system.INI file refers to this device, but device file no longer exists. If you deleted this file on purpose, try uninstalling the associated application using it's uninstall or setup program.If you still want to use the application associated with this device file try reinstalling that application to replace the missing file.press any key to continue."
after pressing a key this pops up...
C:\progra~1\grisoft\avgfre~1\avg7core.vdx
press again...
C:\progra~1\grisoft\avgfre~1\avgtdi.vdx
press the third time...
C:\progra~1\grisoft\avgfre~1\avg7rs
then my computer starts. I've downloaded and run "CCleaner" and found 38 avg's in my registry. tried to fix this with no luck. I went to start, run, regedit
and under the path HKEY_LOCAL_Machine software I found a grisoft file.
I'm thinking I should just delete anything to do with avg or grisoft in my registry. My end result is trying to free up any space I can as in this old HP Pavilion. It only has a 14.2GB hard drive with 474MB left. This also leaves me with a download problem as to how much space I have left. I do have AdAware which I have run to clean things up.
Any help would be appreciated. thanks for your time, Bill

 

thank you plodr & DomLuc. my computer now starts fine. although the 32 bit download wouldn't work (program performed a illegal operation,invalid page fault) the filehippo download did the trick.(had to do the install then uninstall) I did run the ccleaner several times after manual delete of the registry. this didn't do much to make some space as I hoped. so I guess I'm going thru and start deleting some programs I have never had a need for. (quicken basic 2000 for example).
thanks again, Bill