Help! Dell 1355cnw Prints Vertical Colour Lines and Blotches

Question

Question = Have I messed my printer drum and/or belt?
History = My 1355cnw recently started printing short vertical magenta scuff lines at the tops of each page over the same 15mm width in the same place each time. I cleaned the fuser with IPA and used the toner cleaning wand on the toners to no effect. 
I the used an airduster to blow out all the dust and loose toner from all accessible angles/ holes in casing
Doing this prevented the paper pickup shoe from working as it had become contaminated with dust so i fed a piece of paper partially dampened with IPA into the printer via the tray printing a blank page - it came out dry but there are now scuff marks of all colours across the width of the page :o( 
The first page printed of several blank pages also has repetitive colour toner coloured blotches up the page.
Post print opening the back door reveal toner on the transfer belt and the sponge grip wheel where i'm sure I haven't seen it before.
Additionally, since this incident i am now seeing scuff marks being transfered onto the non-print of the paper - presumeably from all the loose toner flying around.
I have printed out the 4 colour configuration chart and the drum refresh configuration chart and they both have the same sreak paterns down them (JPGs available) but they look a mess!  They look like a grand prix started on them!
Have I messed my printer and if so which bits?  Any and all help offered is greatly appreciated to cover my blushes in making the print issue 100 times worse!!
Thank
Andy

Answer 1

Reply much appreciated. Although I do not claim to have much knowledge of this type of hardware and software problems but they do give me a challenge. I have been trying various things. while I was doing this, switching the pc on and off, at one point the display on LCD came back.
When I checked the status in Device manager the error message,'WINDOWS HAS STOPPED THIS DEVICE AS WINDOWS HAS REPORTED PROBLEM (CODE 43) had disappeared and it said.' The device is working properly'!
I notice that the CPU temp rises upto about 51 deg C, the fan goes crazy (fast and slow)and the temp falls down and fluctuates between 27 and 48.
The screen goes blank again and come on some time and most times not!
To me it looks like that the chipset gives up when too hot. 
I intend to open up the laptop and see if the GPU chip is seated, has good contact with its heatsink etc.
If anyone has any further suggestions, will be appreciated.