Dell 8200 freezes or forever to sign in

Dimension 8200 1.7 p4, 512ram, XP sp2
Computer runs like a champ while offline but while signing in to MSN takes forever or even freezes up. When home page does come up it is not completely loaded and the color on the page is dull and nothing can be clicked while waiting for it to finish loading. If I try to pull up the task manager or any other program during this "limbo Time" it will not appear until all the color in the home page fills in (signifying completion of homepage loading up) Then all at once "POOF!" all applications I tried to open appear at once at the same time. Off line all applications or programs load immediately. Even when online after the "Limbo Time" is over and sign in is 100%, pulling up task manager or anything else is a snap. I've run -Spybot-Adaware-Spyware Blaster-Trojan Hunter, all up to date and machine is clean. The OS cd is misplaced so a clean install is not an option. MSN software is good. Is this a modem gone bad? Sometimes during "Limbo" it takes so long that I choose to re-boot instead of waiting on the chance that next time it wont take so long but even then I have to turn it off at the tower because I can't click the start button to re-boot.
Thanks In Advance,-64surfit