plug it in to itunes, sync it let it do a back up etc
on the main page in itunes for your ipad, choose restore.
this will remove all form your ipad reinstall and put it back to how it was.
Has it ever been jail broken
what OS is it running
are the partcular apps still supported on the OS
apple release updates ever so often, if the person who wrote the app doesnt keep up quie often the app becomes unstable.
just make sure every thing is kept uptodate.
resore fixes most software /corruption issues takes about 20 mins