white screen

I have a site... rsa1.ajaja99.com that like to go blank.... completely blank. It happens after I activate a new module. GeoUser seems to be an issue a lot.

the problem I believe is that I am running to many modules, or perhaps a faulty one.

My solution so far is to:

go into the system table and update the status field of specific modules from 1 to 0.

is there a better way to back out of activating a module? I have learned to do one module at a time.

the other problem is that I can not seem to get the modules to UNINSTALL. Again, I get a white screen.

I am throwing in the towel and starting a totally new site, but leaving this site up so people can see it ( although there is not much to see ).

btw, the error I am getting is:
warning: require_once(modules/geouser/geouser.inc): failed to open stream: No such file or directory in /hsphere/local/home/vyoumans/rsa2.ajaja99.com/sites/all/modules/geouser/geouser.module on line 10.

I have run CRON, I have done an update.

so... recap... my questions:
1... is there a way to figure out if I am just running out of hosting resources?
2... Is there a better way to back out of module installs?
3... Is there a way to manually uninstall modules, so I can repair stuff in the future?

thanks