This is a very annoying problem in which internet explorer (sp1)opens in a blank page.
Cause:-It happens if some dll files are not registered.
You have to re-register the dll files.
Start>Run>regsvr32 actxprxy.dll >ok
Start>Run> regsvr32 msxml.dll >ok
Start>Run>regsvr32 shdocvw.dll >ok
Start>Run>regsvr32 browseui.dll >ok
Now restart your computer and open internet explorer.
But I think best option is to switch over to Service pack 2.