Battery & Trip Computer Problem

[celticdarren]

So I tried my car yesterday 5 minutes after I had drove it for the first time in about 5 days and it wouldn't start. Tried it again this morning and same thing.

Got a jump start and it worked! So took it a long run then let it tick over for a while. Turned it off and left for 30 minutes and then I tried it again, but took 2 attempts to start up. I put it down to a dodgy battery. Got a new one and fitted it. Car started perfectly (apart from telling me it needs serviced but I reset this). I then started to drive and the average MPG shot up to 99.9, and the average speed hit about 300MPH!

Does my trip computer need reset or is something else wrong?

Thanks in advance, Darren.