Your original question is here.  Nonetheless, unless these are online games
and the online gaming is what is slow, these are not likely to be the issue.

What type of connection do you have, broadband or dial-up?  If dial-up, what
speed are you getting.

Is this a recent issue?  If yes, you might try using System Restore to take
you back to a time prior to when this began.  Start\All
Programs\Accessories\System Tools\System Restore.

You might try clearing the browser cache.  Open Internet Explorer, go to
tools, select Internet Options, click Delete Cookies, Delete Files (Accept
the option to delete all offline content) and click clear history.

You might also make sure your antivirus software is up to date and run a
virus scan on your system.

Also, download, install and run Ad Aware:
www.lavasoftusa.com

Not sure what you mean by setup user accounts for just those games but
essentially, you'd create the user account, while the account is still an
administrator account, install the game or games, then, change it to a
limited account.  This should allow the user to continue to play the game
but have limited access to other things.  NOTE: because most applications
were not designed for a multi-user environment, you would need to do this
for each new user you create for which you wish to grant access to those
games.