Hi Dorothy, A check sum uses an algorithm which can produce a long number which represents in 128 or 160 digits the content of the file. It is possible to run a utility against a downloaded file which can reproduce this number and check it against the number produced from the same check which might have been performed at the server in order to check that a file hasn't been corrupted during a download. If you wish to investigate further, md5 and shah1 would bring up interesting results on a Google search. Regards, Phil Medway philmedway@xxxxxxxxxxxxxxxx tel: 01869 347639 mobile: 07980 519990 Skype: philmedway ----- Original Message ----- From: "Dorothy Ingram-Gorban" <dorothy.ingram-gorban@xxxxxxxxx> To: <jaws-uk@xxxxxxxxxxxxx> Sent: Thursday, February 01, 2007 10:44 AM Subject: [jaws-uk] Steve Thompson Spybot Updates. Sorry this is not on Spybots but you mentioned a Checksum Error can you explain just what a Checksum error is? I had it once on a former computer and no one seemed to know in my case it was a Battery failure Dorothy. ** To leave the list, click on the immediately-following link:- ** [mailto:jaws-uk-request@xxxxxxxxxxxxx?subject=unsubscribe] ** If this link doesn't work then send a message to: ** jaws-uk-request@xxxxxxxxxxxxx ** and in the Subject line type ** unsubscribe ** For other list commands such as vacation mode, click on the ** immediately-following link:- ** [mailto:jaws-uk-request@xxxxxxxxxxxxx?subject=faq] ** or send a message, to ** jaws-uk-request@xxxxxxxxxxxxx with the Subject:- faq -- This email has been verified as Virus free Virus Protection and more available at http://www.plus.net ** To leave the list, click on the immediately-following link:- ** [mailto:jaws-uk-request@xxxxxxxxxxxxx?subject=unsubscribe] ** If this link doesn't work then send a message to: ** jaws-uk-request@xxxxxxxxxxxxx ** and in the Subject line type ** unsubscribe ** For other list commands such as vacation mode, click on the ** immediately-following link:- ** [mailto:jaws-uk-request@xxxxxxxxxxxxx?subject=faq] ** or send a message, to ** jaws-uk-request@xxxxxxxxxxxxx with the Subject:- faq