Windows

Well I must have been spoiled. AS much as I have waited for Doom3 ( and am still holding return to wolfestien ) I haven't been around to notice that for the first time since 1998, checking the operating system on sytem requirements was needed. Found out the hard way and now I am bummed. At first I figured ok they do not officially support win 98, doesn't mean it won't run untill I get xp AFTER the service pak fix. WEll It won't load at all. SO what I am asking in the round about way, is: is there some tweak I can use to get by untill I upgrade ( as in disable the game from checking for the operating sytem when loading ) Or is win 2000 or xp actually required for some of the games functions. Also I need some advice for upgradeing. I have win 98 upgrade and an oem win 95. And my hard drive is 80 gigs so with the win 98 I have to use a third party utility to optimise and use the entire hard drive. I understand I may have difficulty installing the windows xp upgrade? And any hint other than ebay I can have to get a legal copy of big brothers Win xp Upgrade for less than $99 would be appreciated. I am a huge fan Doom and Doom2 and Castle wolfeinstien, and the heretic hexen series. Disapointed in all quakes but happy with Unreal, I designated Doom 3 for ID softwares big return to my hard drive. ( and if half of what I hear about half life is true I will get half life 2 ) And am actually feeling a bit nerdy because I am sad I cannot play it :( help.