HP Digital Scanner 9250c issues

I have two HP Digital scanners 9250c, it will sometimes pull a document to the left and not scan it and also have problems clearing jams?

It also keeps saying service is busy and will say at the beginning of a scan, there is a jam on the glass but there are no documents on the glass?

Also you have to hit the first letter of your user name several times before it shows up in the user ID box.


Thanks

Replace the rollers in the ADF, also check the paper sensors and reseat the connection to the main scanner. About the letter, it's probably just bad, replace that as well if you can.