Tackle one at a time. There are some Scandisk troubleshooting steps listed
here:
http://home.satx.rr.com/badour/html/scandisk.html
TROUBLESHOOTING SCANDISK PROBLEMS

Richard

Start by downloading  Adaware and / or update Reference file from http://www.lavasoftusa.com/support/download/ 
and use it to remove parasites.

How good is your housekeeping?

1. In Outlook Express empty your Deleted Items folder.

2. In Outlook Express run File, Folder, Compact All whilst OFFLINE.

3. Remove Temporary Internet Files by selecting Start, Settings, Control Panel, Internet Options, General tab, Delete Files and check box for "Delete all offline content". Also Delete Cookies and Clear History.

4. Empty Recycle Bin.

5. Run Disk Defragmenter in Safe Mode.  Running in Safe Mode may be slower than in normal mode but generally is more certain to eliminate the restarting problem coming from other programmes writing to disk.

To start Windows in safe mode Click Start, and then click Shut down. Click Restart, click OK, and then press and hold the CTRL key until the Microsoft Windows 98 Startup Menu appears. For some machines, you can use F8 instead of CTRL to bring up the Microsoft Windows 98 Start-up Menu. Enter the number for Safe mode, and then press ENTER.