And to add to what @Tori B said...
I would NOT uninstall QBs or Delete the Company file until you are sure that the QBs installation is working properly on the new computer. (Assuming this is not a company machine you have to give back right away.)
Also, you can put your Company file anywhere you want on the new machine. So if you're in a habit of making extra Backups of your Document folder or whatever, put create a new QuickBooks Data folder there. I personally have a Data Folder that I move all of my User Data from all programs, including Documents, Desktop, Photos, etc. In addition to a full backup, I just make a copy of that folder on a regular basis to have a second non-compressed copy of the data. (Use a little comparison program so I don't have to recopy the unchanged files.)
Once you've copied over your Company file to the folder you want it in, then install QBs. When it finishes the installation you'll be at the No Company Open box and one of the options at the bottom will be to Open or restore an existing company. Click on that and follow the prompt to find where you put your Company file.
You probably should go to Help and Update QBs before you start to do any work.
You should also move all of your Backup Files to the new machine. If you have more than one Drive on the new machine, put the BU files on the OTHER drive. Then if you have a drive failure (either one) you will not loose all of your data. When you run Backup for the first time, just follow the prompts to find the folder your BU files are in. If you only have one drive, QBs is going to warn you about this. If you don't have a choice, then accept the warning and say you want to continue to use the same drive.
If you do only have one drive. Maybe every Friday you copy off the QB file to a USB drive and lock it up someplace safe. If something happens (fire, flood, robbery, etc.) you will at least have your data since your last copy.
Once you're done and everything has been working for a while - including the new computer - you can delete the files off the old one.
