It depends on what you mean by old. An old Dell desktop from way back in 2011 can probably be easily overclocked, but a recent Dell desktop from 2004 might be impossible to overclock.
just take out your previous hard drive and shift the jumper at the back of the drive from master to slave position. And fit it in your new desktop.
by unhidding them
Right click on desktop>properties>desktop>click customize desktop>click web tray>uncheck lock desktop items then click ok..
desktop
You can get desktop back ground simply by looking up your favorite back ground type and saving it to your computer. You can then go to your settings and make it your background.
Go to where the bin is, usually in the Start menu; right-click it; select Send; select To desktop.
You can go to your mobile desktop features of Laptop Desktop Features to change the wallpaper of your device. When you select a new background, it automatically replaces the old background.
Go to the recycling bin. And find "desktop" click it and hit "restore". And it then hit the start button. In the search bar type in "desktop". If that does not work I am sorry. But I am sure it will work.
System->Preferences->Desktop EffectsClick on the button labelled 'Enable Desktop Effects'Log out, then log back in.
yes
Assuming you mean the "Show Desktop" button, you right click the start back and click "Properties" then check "Show Quick Launch".