Hi Agnes,
If it hasn't already been done, a maintenance plan(s) should be created for backups, index defrags, tranlog truncation, etc.
Assuming there is a DBA, ask him/her to set it up. Otherwise, you can learn how to do it.
And, NO, do not delete the transaction log. And, YES, it is too big.
Look here:
http://support.microsoft.com/kb/272318>Recently , I find that there is timeout occur when runing 'select .
>statement'
>Some said the Transaction Log too large will make SQL become slowly
>
>Now, the transaction log is 14407M , is it too large ? Can I delete it ? (Do
>I need to do backup first ?)
- Jeff