Outlook is not downloading all the emails..

Dear Sir..

i have 2 pcs,

PC1 - 1 laptop (Win 7 Professional)
PC2 - 1 desktop (Win XP)

i have 4 emails configured in Outlook 2007 on both systems.
also on both pc, i put the option " leave a copy of message on server.."

PC2 is downloading all the emails from the mail server..
but PC1 is not..
when i checked in the mail server, all the mails are there only.

the problem is only for that laptop..
can anybody help me to solve this..

waiting for ur quick reply..

thanks..

sibin

thanks for ur reply..

it does only sometimes..
if today i've received 20 emails, PC1 'l download only 3 or 4..

PC1 has Norton Antivirus 2011
PC2 has Norton Antivirus 2010

thanks..

I have solved it..

Norton antivirus was the problem..
i have turned off "Scan Incoming Emails"..

now its working fine..

thanks for ur help..
thanks Windows seven forum..

I have one PC with 2 users. For one user it works perfectly but for the other it downloads only about 1 in 3 emails. I don't use Norton but McAfee.