Complex sentence: Andrew is very keen at working with computers, his teachers at Eston Park said he was very good when using computers and seemed to know quite a lot while he was using them, at times he did ask for help when he was having a few problems.
Split into simpler sentences: Andrew is very keen at working with computers; his teachers at Eston Park said he was very good when using computers and seemed to know quite a lot while he was using them. At times, he did ask for help when he was having a few problems.