First, make sure Fences is removed, didn't leave its detritus behind and cannot do any harm, if it's the culprit. You can always put it back once your search for a solution is completed.
The cleanest, ideal way to do that is to perform a system restore to just before installing it. But you don't necessarily have a restore point, and it might be inconvenient. If you can,t do that:
Uninstall it through the control panel
Remove all folders with its name (search for them with Windows explorer)
(Not really necessary, but you could also use a cleaning program like CCleaner that would wipe registry entries from this program.)
Once Fences has been removed entirely, see if you still have the issue.
If you do, then I say your computer might be in need of a good maintenance.
Look around the Task Manager if there are programs at startup that seem suspicious and disable them.
Run a thorough antivirus/anti-malware scan on your computer. Avast! Free does this fine. I suggest a scan on startup (or however it's called in English). That's most effective. You know, that thing where the scan runs before Windows is launched, in a MS-DOS style interface.
Clean all leftover registry entries with software such as CCleaner.
Defragment your disc.
There might be other things to check, but if you don't solve the issue with those things, you might have to format your computer if you want it back to normal. Sometimes, despite protection, despite antivirus scans, despite cleaning whatever there is to clean, you just can't find why the computer has slowed down or is having weird bugs. Problems build up over time, and you can't really see and fix them all individually. Maybe something that happened recently was just the drop that made the vase wet the table. I personally think it's healthy to format a computer once in a while. And even though it's a pain to do, after doing it, things (almost) always go so much better than before.