Try this. Right click on the IE icon and open Properties. Make sure the "Run" drop down menu is set to "Normal window". Then click Apply > OK.
If it is already set to "Normal window", then open the drop down menu and click on "Normal window" > Apply > OK to reset it.
If the Problem persists clean out the Temporary Internet and History files.
If the problem continues to persist perhaps System restore to a date/time prior to when the problem began may undo the problem.
If still the problem persists download, install and run IEFix - General purpose fix for Internet Explorer
Hope something here is helpful.
I have a desktop eMachines T1840 running Windows XP Professional (over Windows 2000 Pro). It has worked fine since I installed the OS but this past week I began having problems opening Internet Explorer. When I hit the icon to launch it, it opens briefly then disappears into the right side of my monitor screen. I can still access the internet but I have to go to "My Computer" and type in the site address there. I talked to my IT people at work and they don't have a clue as to why it does this so, any answers or remedies will be greatly appreciated.