Spyware Doctor is not one we recommend. Which anti-virus, or do you mean the one that comes with Spyware Doctor? If so, Spyware Doctor is not one we recommend.
Startup problems are, more often than not, caused by too many Startup files. A system with insufficient memory, (RAM), is also a factor but since you provide no details of your system specifications I must assume your system has sufficient RAM.
So, back to Startup files. When Windows loads it will load all the software that you have set to load at Startup. If there is too much, this will slow startup considerably, so I would suggest you review the software you have set to load at Startup, or software that, when installed, you allowed it to set itself to load at Startup.
You can begin that review process by using the System Configuration Editor, often just called MSCONFIG. Goto Start > Run, type in msconfig, and click OK. In the System Configuration Editor go to the Startup tab and remove the ticks for all the unnecessary software that is loading at Startup. Typically these are 'Real Player products' 'Quicktime', any Instant Messengers, any other media players, any 'Quick Launch' like Firefox or other browsers, anything where it is just as easy to launch the software from your Desktop icon or Start Menu shortcut.
Google will help you identify any entries you are unsure about.
I would also download, install, update, and perform a "Full Scan" with one of the two manual anti-malware scanners noted below;
Malwarebytes' Anti-malware or
I would also review your choice of anti-virus scanner.
I have been frustrated that everytime I open my computer, it starts up very slow and sometimes it takes more than 2 minutes before you can actually click something. One thing more is that every time I open programs, it takes like 30 seconds to open completely. When I shift from one program to another, the minimized window is too slow to close or minimize.
I have spyware doctor and antivirus.
What could be the problem when I wasn't able to detect any spyware or virus? What will I do??