1. CLick on Tools from inside internet explorer.
Click Internet Options
Click delete files in the middle of the page
Click on Settings
UNder Check for newer version of stored pages choose every visit to the page. (You are pulling cached pages from the hard drive. This will fix your first problem.
2. ISDN is 2 56K lines wired together so to speak. You need a special Modem for them. This is pricey. I would go with a satellite before I went ISDN. Mostly commercial businesses use ISDN.
3. Aaare you using windows 98, 2000, xp or ME? Check your power settings in control panel. Check power settings under BIOS.