There are some useful guidelines for IE7. After downloading but before you install disable your anti virus. Some Avs can affect installation.
If you have add ons like extra toolbars then its a good idea to get the latest versions from places like Google (if you use theirs) so they are IE7 compliant.
If you have difficulties initially then go to tools, internet options, advanced tab and click on the reset browser button. The effect is to disable add ons (amongst other things) and you can add them back in until you discover which one if any is non compliant.
I have two machines both running IE7 flawlessly. If ultimately you do not like it there are plenty here who will recommend Firefox or uninstalling IE7 to roll back to IE7.